In vivo articular contact pattern of a total wrist arthroplasty design

Finite Element Modeling of the Human Wrist: A Review

Background  Understanding wrist biomechanics is important to appreciate and treat the wrist joint. Numerical methods, specifically, finite element method (FEM), have been used to overcome experimental methods' limitations. Due to the complexity of the wrist and difficulty in modeling, there is heterogeneity and lack of consistent methodology in the published studies, challenging our ability to incorporate information gleaned from the various studies. Questions/Purposes  This study summarizes the use of FEM to study the wrist in the last decade. Methods  We included studies published from 2012 to 2022 from databases: EBSCO, Research4Life, ScienceDirect, and Scopus. Twenty-two studies were included. Results  FEM used to study wrist in general, pathology, and treatment include diverse topics and are difficult to compare directly. Most studies evaluate normal wrist mechanics, all modeling the bones, with fewer studies including cartilage and ligamentous structures in the model. The dynamic effect of the tendons on wrist mechanics is rarely accounted for. Conclusion  Due to the complexity of wrist mechanics, the current literature remains incomplete. Considering published strategies and modeling techniques may aid in the development of more comprehensive and improved wrist model fidelity.

Correlation between carpal rotational alignment and postoperative wrist range of motion following total wrist arthroplasty

BACKGROUND

Although total wrist arthroplasty (TWA) has become a common treatment option for wrists with damage due to rheumatoid arthritis (RA), the optimal implant axial alignment for TWA has been inadequately studied. This study was performed to investigate the relationships between implant alignment and carpal rotational alignment and the wrist range of motion (ROM) following TWA.

METHODS

This study included 18 patients who underwent TWA using a DARTS® Total Wrist System (Teijin Nakashima Medical, Okayama, Japan) for wrist RA. Pre- and 6-month postoperative computed tomography scans were performed, including the radial volar line (Rv), capitohamate axis (CH), and Rv-CH angle in axial scans. The wrist ROM was also measured. The relationship between the Rv-CH angle and ROM was examined.

RESULTS

The mean Rv-CH angle showed significant wrist pronation from 73.0° to 83.4° postoperatively. We observed a significant positive correlation (0.58) between the postoperative Rv-CH angle and extension and a significant negative correlation (- 0.56) between the postoperative Rv-CH angle and flexion.

CONCLUSIONS

Implantation of the DARTS® TWA prosthesis resulted in pronation of the carpal axial alignment, which was correlated with postoperative wrist extension. The volar cortex of the distal radius can be a novel reference axis for adequate implant placement.

Musculoskeletal Modeling of the Wrist via a Multi Body Simulation

In this study, three different musculoskeletal modeling approaches were compared to each other. The objective was to show the possibilities in the case of a simple mechanical model of the wrist, using a simple multi-body-simulation (MBS) model, and using a more complex and patient-specific adaptable wrist joint MBS model. Musculoskeletal modeling could be a useful alternative, which can be practiced as a non-invasive approach to investigate body motion and internal loads in a wide range of conditions. The goal of this study was the introduction of computer-based modelling of the physiological wrist with (MBS-) models focused on the muscle and joint forces acting on the wrist.